1. Field of the Invention
This invention relates to a slurry for chemical mechanical polishing (CMP), a polishing method, and a method of manufacturing a semiconductor device. In particular, this invention relates to a CMP slurry for metallic film, a polishing method of a metallic film, and a method for manufacturing a semiconductor device using a damascene wiring.
2. Description of the Related Art
A Cu damascene wiring to be mounted on a high-performance LSI has been formed by using CMP. In this CMP, the polishing is performed in two steps, i.e., a first polishing where the abrasion of Cu is mainly performed, and a second polishing where the abrasion of redundant metal and insulating film is performed. In the first polishing, Cu is abraded at a rate of 800 nm/min or more while substantially preventing a barrier metal such as Ta and Ti from being abraded. It is demanded, in this first polishing, to suppress the dishing of Cu to 20 nm or less. When a Low-k material is to be employed as an insulating film, the peeling of film or the fracture of film itself would occur if the polishing friction is large. Therefore, it is now becoming difficult to employ the conventional CMP slurry which is inherently large in polishing friction.
In the case of the second polishing also, it is desired, as in the case of the first polishing, to perform the polishing at low friction so as to enhance the affinity between a polishing surface and a polishing pad and to minimize the scratch of Cu, the corrosion of Cu and the scratch of insulating film, thereby suppressing the dishing of Cu as well as the erosion of insulating film. Since the conventional silicone-based surfactant acts strongly on silica employed an abrasive particle to generate coarse particles thereof, it is difficult to suppress the generation of scratch of Cu or the insulating film and to stabilize the polishing rate.
With a view to meet the requirements in the aforementioned first polishing and second polishing, there has been proposed to employ a slurry where polyvinylpyrrolidone (PVP) is used. However, no one has succeeded to obtain a slurry which is excellent in stability and, at the same time, capable of suppressing the dishing or corrosion of Cu and the scratch of insulating film in the formation of Cu damascene wiring. Therefore, there is no slurry at present which is capable of sufficiently meeting the performances demanded of the LSI of the next generation.